World’s Soil Resources

Figure 6.9 Historical and predicted shift of the urban/rural population ratio. Source: UN, 2008.
6.7 | Soil sealing: status and trends
For millennia, the vast majority of people lived a rural life, largely dependent on agriculture and other rural
occupations. Only over the last two centuries has the ratio between the urban and non-urban population
started to change rapidly. In 1800, only 3 percent of the world’s population lived in cities; in 1900 14 percent,
47 percent in 2000, 50 percent in 2007, and 54 percent in 2014. The proportion of the urban population is
expected to rise to 66 percent by 2050 (Figure 6.9).
The world’s urban population is growing and cities are expanding in order to accommodate the increasing
population and economic activity. It is not known with any certainty what share of the Earth’s land surface (ca.
144 million km 2 ) is now occupied by cities or how much land will be required to accommodate the expected urban
expansion (Potere et al., 2009). One of the most accurate estimates of the extent of urban areas at global scale,
based on the use of MODIS satellite data at a resolution of 500 m, indicates for the year 2000 an area of 657 000 km 2
(Potere et al., 2009), equivalent to 0.45 percent of the Earth’s land surface. Urbanization is an important contributor
to regional and global environmental change (Foley et al., 2005, Ellis and Ramankutty, 2008). The growth of cities has
a vast impact on the landscape and significant impact on soil resources (Chen, 2007; Gardi et al., 2014).
Status of the World’s Soil Resources | Main Report Global soil status, processes and trends
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